Ijland Marloes M, van Doorn Jeroen L M, Beukman Axel, van der Hoeven Johannes G, Lemson Joris, Heunks Leo M A, Doorduin Jonne
Department of Intensive Care Medicine, Radboud University Medical Center, Postbox 9000, Nijmegen, 6500 HB, The Netherlands.
Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
BMC Pediatr. 2025 Jul 2;25(1):502. doi: 10.1186/s12887-025-05827-x.
Respiratory muscle weakness is common in critically ill children. Changes in respiratory muscle structure play pivotal role in the development of weakness. Echogenicity is a non-invasive marker to detect structural changes in skeletal muscles. In this study, we evaluated respiratory muscle echogenicity in critically ill ventilated children at PICU admission compared to a control group and its change over time. Secondary, we explored its association with clinical parameters and outcome.
Two cohorts were studied: a secondary analysis of a prospective longitudinal observational cohort study in mechanically ventilated children (n = 32) and a prospective control group (n = 13) for obtaining reference values. Ultrasound images of the diaphragm and expiratory muscles were analysed. Muscle echogenicity, muscle thickness, muscle thickening fraction, clinical parameters (inflammation, fluid balance and protein intake) and clinical outcome measurements (ventilation free days, extubation failure and 28-day mortality) were collected.
The analysis included 174 diaphragm ultrasounds and 144 expiratory respiratory muscles ultrasounds. Echogenicity at PICU admission was not different from controls; for the diaphragm: 27.3 [20.0-32.0] vs 26.3 [19.3-29.3] (P = 0.488), m. obliquus externus: 32.2 [25.5-37.9] vs 34.0 [28.0-51.3] (P = 0.166), m. obliquus interna: 29.8 [25.8-38.8] vs 33.0 [27.8-39.3] (P = 0.390), m. transversus: 30.0 [20.8-38.8] vs 32.3 [24.7-37.0] (P = 0.762), respectively. There was no increase in respiratory muscle echogenicity after four days of mechanical ventilation, though a substantial interindividual variation existed. No correlation was found between changes in echogenicity and changes in muscle thickness, thickening fraction and echogenicity on day four of mechanical ventilation, or clinical outcome. The intra-observer repeatability of the echogenicity for all the respiratory muscles was excellent (all ≥ 0.97).
In critically ill children, four days of mechanical ventilation does not result in an increase in respiratory muscle echogenicity. Our findings suggest that short periods of mechanical ventilation with relatively low ventilator setting in moderate critically ill children do not lead to large structural changes in the respiratory muscles.
呼吸肌无力在危重症儿童中很常见。呼吸肌结构的变化在肌无力的发展中起关键作用。回声性是检测骨骼肌结构变化的一种非侵入性标志物。在本研究中，我们评估了危重症机械通气儿童在儿科重症监护病房（PICU）入院时与对照组相比的呼吸肌回声性及其随时间的变化。其次，我们探讨了其与临床参数和预后的关联。
研究了两个队列：对机械通气儿童进行的前瞻性纵向观察队列研究的二次分析（n = 32）和一个前瞻性对照组（n = 13）以获取参考值。分析了膈肌和呼气肌的超声图像。收集了肌肉回声性、肌肉厚度、肌肉增厚分数、临床参数（炎症、液体平衡和蛋白质摄入量）以及临床结局指标（无通气天数、拔管失败和28天死亡率）。
分析包括174次膈肌超声和144次呼气肌超声。PICU入院时的回声性与对照组无差异；对于膈肌：27.3 [20.0 - 32.0] 对比 26.3 [19.3 - 29.3]（P = 0.488），腹外斜肌：32.2 [25.5 - 37.9] 对比 34.0 [28.0 - 51.3]（P = 0.166），腹内斜肌：29.8 [25.8 - 38.8] 对比 33.0 [27.8 - 39.3]（P = 0.390），腹横肌：30.0 [20.8 - 38.8] 对比 32.3 [24.7 - 37.0]（P = 0.762）。机械通气4天后呼吸肌回声性没有增加，尽管存在很大的个体差异。在机械通气第4天，回声性变化与肌肉厚度、增厚分数和回声性变化之间以及与临床结局均未发现相关性。所有呼吸肌回声性的观察者内重复性极佳（均≥0.97）。
在危重症儿童中，4天的机械通气不会导致呼吸肌回声性增加。我们的研究结果表明，在中度危重症儿童中，使用相对较低呼吸机设置进行短期机械通气不会导致呼吸肌出现大的结构变化。
